GMail: How Long to Implement a Changed Verification-code Tel#?

I signed up for GMail ~4 years ago, to use for one specific group endeavor where the group leader specified “everybody on GMail please”. Then didn’t use it subsequently. Lately I’ve been thinking I’d resurrect it. I am able to log into it via web browser, send and receive emails, get into account settings, etc.

I don’t, however, want to use it in a web browser.

To fetch email and send email from an “outside” application, I need to set an annoying flag in security about “allow less secure connections”. To set the annoying flag to that value, I have to verify that I’m really me, by receiving a text and plugging it in to the blank field on the web screen. Yeah fine but the phone number I put in back then doesn’t go to a cell phone so no text can be received. (I have an email address associated with the account too, but it doesn’t offer the option of emailing me a confirmation code. I see a “more ways to verify” button but when I click it it just refreshes to the same “we’re poised to send a text to your phone”).

I changed my security phone# four days ago. But when I invoke the “yes I want to allow less secure connections” thingie, it says it’s going to send a text to the phone number ending in the last couple digits of the OLD phone number, so it hasn’t gone through in a meaningful way yet.

Any idea how long it takes for this change to proliferate?